The present invention relates to a multilayered polymeric body comprising multiple optical thickness layer types, at least a portion of which are in a folded relationship, which body reflects light and which can be fabricated to have an iridescent or silvery appearance; to decorative articles produced therefrom which may find use as wall panels, dishware, and decorative trims; and to security articles produced therefrom which may find use in anticounterfeiting applications.
Highly reflective articles (i.e., articles having a reflectance of 70-85% or greater) are generally sought by industry for a number of uses. Conventional methods for fabricating reflective surfaces include forming such surfaces of highly polished metals. However, because of the high costs and fabricating problems involved in using metals, more recently fabricators have used plastic surfaces which contain thin coatings of metal thereon. Thus, metal coated plastic articles are now commonly found as both decorative and functional items in a number of industries. Such articles are used as bright work for consumer appliances such as refrigerators, dishwashers, washers, dryers, radios, and the like. These types of articles are also used by the automotive industry as head lamp reflectors, bezels, radio knobs, automotive trim, and the like.
Typically, such metal coated plastic articles are formed by electroplating or by the vacuum, vapor, or chemical deposition of a thin metal layer on the surface of the article. However, such coatings are subject to the chipping and flaking of the metal coatings as well as corrosion of the metal over time. If additional protective layers must be applied over the metal coating to protect it, additional labor and materials costs are involved. Further, there may be environmental disposal problems with some metal deposition processes.
Multilayer articles of polymers are known, as are methods and apparatuses for making such articles. For example, such multilayered articles may be prepared utilizing multilayer coextrusion devices as described in commonly-assigned U.S. Pat. Nos. 3,773,882 and 3,884,606 to Schrenk. Such devices are capable of simultaneously extruding diverse thermoplastic polymeric materials in substantially uniform or varying layer thicknesses. The number of layers may be multiplied by the use of a device as described in commonly-assigned U.S. Pat. No. 3,759,647 to Schrenk et al.
Im et al, U.S. Pat. No. 4,540,623, teach a multilayer laminated article which includes a polycarbonate as one of the alternating layers. The articles of Im et al, however, are intended to be transparent rather than reflective and to exhibit optical properties comparable to a pure polycarbonate polymer.
Alfrey, Jr. et al, U.S. Pat. No. 3,711,176, teach a multilayered highly reflective thermoplastic body fabricated using thin film techniques. That is, the reflective optically thin film layers of Alfrey, Jr. et al rely on the constructive interference of light to produce reflected visible, ultraviolet, or infrared portions of the electromagnetic spectrum. Such reflective optically thin films have found use in decorative items because of the iridescent reflective qualities of the film.
However, because the film relies solely on the optically thin layers, such films are limited to uses requiring iridescent reflective properties and are not practical for uses which require a silvery or colorless reflectivity.
In the security field, artisans have used optically variable reflective devices on credit cards and currency in attempts to foil counterfeiters These reflective devices include metal and prismatic foils, embossed foils, and holographic foils which can be incorporated onto or into credit cards and the like. Baird et al, U.S. Pat. No. 3,858,977, teach the use of optically thin iridescent films as an anticounterfeiting device. However, the costs of fabrication of these devices make them expensive to use. Further, many of these devices require the use of metal to obtain their reflective properties.
Accordingly, there remains a need in the art for a highly reflective polymeric sheet or body which can be post formed into a variety of decorative and useful reflective items. Further, there is a need for iridescent, silvery or metallic appearing articles which do not use metal.